ISBN 9783843946520

978-3-8439-4652-0, Reihe Ingenieurwissenschaften

Wladimir Reschke
Particle-Based Modelling and Simulation of Heterogeneous Reactions

156 Seiten, Dissertation Universität Stuttgart (2020), Softcover, A5

Zusammenfassung / Abstract

Experiments to investigate technical flows involving heterogeneous reactions are often expensive or technically not feasible due to their complexity. Usually, numerical simulations offer an alternative. However, conventional methods for such simulations are subject to limitations and provide inaccurate results. The following study focuses on the optimization of simulations for gas-surface interactions in the two fields catalytic reactions and evaporation of microscopic droplets.

The aim of this thesis is to adapt and investigate a kinetic surface model that avoids the use of special fitting of model parameters and is applicable to a wide range of catalytic flows. For the modelling of gases, the Direct Simulation Monte Carlo (DSMC) method is used. This method is best suited because of its high degree of accuracy and the possibility to map non-equilibrium effects and strong gradients.

Also, with conventional methods to simulate droplet evaporation, processes on the microscopic level are neglected, which can lead to considerable deviations in predicting the evaporation behaviour of very small droplets. Another goal of this work is therefore the extension of the DSMC method with grid-independent, freely moving and spherical bodies, on whose surfaces both evaporation and condensation processes occur. Thus, the aim is to enable a numerical investigation of evaporating droplets in order to estimate potential benefits of microscopic modelling.

The implementation of the methods in the simulation tool PICLas is verified and tested by comparing the results with analytical solutions, reference solutions and experiments.